feat(kiosk): add android kiosk terminal mode support

完整实现收银终端的Android专用Kiosk模式支持，包括：
- 添加原生设备管理与Kiosk模式核心逻辑
- 新增Flutter设置页的Kiosk相关配置与控制UI
- 更新README添加部署命令
- 补充Android权限与组件声明

lib/common/utils/app/app_runtime_tool.dart

@@ -18,6 +18,75 @@ class AppRuntimeEnvironment {
   }
 }
 
+/// Android 专用设备模式的实时状态。
+class AppKioskStatus {
+  final bool deviceAdminActive;
+  final bool deviceOwner;
+  final bool available;
+  final bool active;
+  final bool lockTaskPermitted;
+  final bool autoEnterEnabled;
+  final bool bootAutoStartSupported;
+
+  const AppKioskStatus({
+    required this.deviceAdminActive,
+    required this.deviceOwner,
+    required this.available,
+    required this.active,
+    required this.lockTaskPermitted,
+    required this.autoEnterEnabled,
+    required this.bootAutoStartSupported,
+  });
+
+  const AppKioskStatus.unavailable()
+      : deviceAdminActive = false,
+        deviceOwner = false,
+        available = false,
+        active = false,
+        lockTaskPermitted = false,
+        autoEnterEnabled = false,
+        bootAutoStartSupported = false;
+
+  factory AppKioskStatus.fromMap(Map<dynamic, dynamic>? data) {
+    return AppKioskStatus(
+      deviceAdminActive: data?['deviceAdminActive'] == true,
+      deviceOwner: data?['deviceOwner'] == true,
+      available: data?['available'] == true,
+      active: data?['active'] == true,
+      lockTaskPermitted: data?['lockTaskPermitted'] == true,
+      autoEnterEnabled: data?['autoEnterEnabled'] == true,
+      bootAutoStartSupported: data?['bootAutoStartSupported'] == true,
+    );
+  }
+
+  bool get canExitToAndroidHome => available && active;
+
+  String get statusLabel {
+    if (!available) return '暂不可实现';
+    if (active && !autoEnterEnabled) return 'Kiosk 运行中 · 自动开启已关闭';
+    if (active) return '可以实现 · Kiosk 运行中';
+    if (!autoEnterEnabled) return '可以实现 · 自动开启已关闭';
+    if (lockTaskPermitted) return '可以实现 · 正在进入';
+    return '可以实现 · 等待策略生效';
+  }
+
+  String get description {
+    if (available && active && !autoEnterEnabled) {
+      return '当前仍在 Kiosk；管理员退出后，再次打开或回到 App 将不再自动锁定。';
+    }
+    if (available && !autoEnterEnabled) {
+      return '设备具备 Device Owner 权限；开启右侧配置后，每次打开或回到 App 都会自动进入 Kiosk。';
+    }
+    if (available) {
+      return '已配置 Device Owner；每次打开或回到 App 都会自动进入 Kiosk，并隐藏主页、最近任务和系统栏。';
+    }
+    if (deviceAdminActive) {
+      return '当前仅激活了设备管理员，仍不能可靠禁用主页和最近任务；需要配置为 Device Owner。';
+    }
+    return '未配置 Device Owner，普通全屏不能保证无法退出；需在恢复出厂或未初始化的设备上部署。';
+  }
+}
+
 class AppNetworkSnapshot {
   final bool connected;
   final String type;
@@ -53,6 +122,7 @@ abstract class AppRuntimeTool {
   );
   static bool _initialized = false;
   static bool _manualHardwareInput = false;
+  static AppKioskStatus _kioskStatus = const AppKioskStatus.unavailable();
 
   static bool get isEmulator => _environment.isEmulator;
 
@@ -65,6 +135,8 @@ abstract class AppRuntimeTool {
 
   static bool get hasMultipleDisplays => displayCount >= 2;
 
+  static AppKioskStatus get kioskStatus => _kioskStatus;
+
   static Future<void> initializePlatform() async {
     if (_initialized) return;
     try {
@@ -72,16 +144,54 @@ abstract class AppRuntimeTool {
         'getRuntimeEnvironment',
       );
       _environment = AppRuntimeEnvironment.fromMap(data);
+      _kioskStatus = await refreshKioskStatus();
     } on PlatformException {
       // 原生通道异常时按单屏处理，避免错误地启动副屏。
       _environment = const AppRuntimeEnvironment(
         isEmulator: false,
         displayCount: 1,
       );
+      _kioskStatus = const AppKioskStatus.unavailable();
     }
     _initialized = true;
   }
 
+  static Future<AppKioskStatus> refreshKioskStatus() async {
+    try {
+      final data = await _channel.invokeMapMethod<dynamic, dynamic>(
+        'getKioskStatus',
+      );
+      _kioskStatus = AppKioskStatus.fromMap(data);
+    } on PlatformException {
+      _kioskStatus = const AppKioskStatus.unavailable();
+    }
+    return _kioskStatus;
+  }
+
+  /// 配置每次进入 App 时是否自动恢复 Kiosk，配置由 Android 原生层持久化。
+  static Future<AppKioskStatus> setKioskAutoEnterEnabled(bool enabled) async {
+    try {
+      final data = await _channel.invokeMapMethod<dynamic, dynamic>(
+        'setKioskAutoEnterEnabled',
+        {'enabled': enabled},
+      );
+      _kioskStatus = AppKioskStatus.fromMap(data);
+    } on PlatformException {
+      // 保留原状态，设置页会据此判断本次配置没有生效。
+    }
+    return _kioskStatus;
+  }
+
+  /// 只有原生层确认 Device Owner/Kiosk 可用时才允许退出到系统桌面。
+  static Future<bool> exitKioskToAndroidHome() async {
+    if (!_kioskStatus.canExitToAndroidHome) return false;
+    try {
+      return await _channel.invokeMethod<bool>('exitKioskToHome') ?? false;
+    } on PlatformException {
+      return false;
+    }
+  }
+
   static Future<AppNetworkSnapshot> getNetworkSnapshot() async {
     try {
       final data = await _channel.invokeMapMethod<dynamic, dynamic>(